Refrigerating apparatus



Jan. 19, 1937. H. J..D|cK

' REFRIGERATING APPARATUS Original' Filed March 17, 1933 reissue Jam-1s; 1937i aoeaov' nnmdnna'imormanafws Herman J; Dick, Dayton, Ohio, assignor, by mesme assignments, to General .Motors Comliionia qrporation.of. l)elaware 1- `Application Mawn'iq, 193s, sensi No'. 661.21' Renewed June-16,1934 J 1 claim: a (ci. 62"-3) u is provided with a bane l1 wh'in extends non. 1

vThe present invention relates'to refrigerating systems and to evaporators for such systems.

7 An object of my invention is'to provide an im'.

proved refrigerating system 'and particularly a. system employing an improved evaporator of the oodedtype. j

Another object'of my invention is to provide an improved flooded evaporator for a refrigerating system, wherein the level of liquid refrigerant is maintained substantially constant by means of a valve actuated in responseto temperatures, the evaporator having all the advantages of an evaporator employinga float operated valve.

` Flnther objects and advantages of the present` invention will be apparent from the following description,v reference being had to the accompany-Y ing'drawing. wherein apreferred form of the present invention is clearly shown.

In the drawing: Fig. l discloses a diagrammatic showing of my f'improvedrefrigerating system connected with an evaporator constructed in accordance with my.

invention;

2'5 closed in Fig. 1 and shows a portion of a heade therefor in section; and

Fig. 24is atop plan view of the evaporator dis- Fig. 3'is -a front view ofthe evaporator shown inFigs.1and2. f Referring -to the drawing,A my improved evaporator includes a pair of headers In. and I I shown as' cylindersdisposed one above the other. v

The-lower' header. I0 is' providedwith an inlet connection I2 for receiving liquid refrigerant. Upper header I I is provided with a gaseous refrigerant outlet connection it. This connection includes 'an extension or stand pipe I5 which extends vto 'a point near the top of header II (see Fig. l) Aand is for a purpose to be later described. A plurality of refrigerant conveying or distribut; ing conduits I d are connected in 'parallel to headers I0 and ii. These lconduits' yiznay be of any desired form and are preferablyof the form as shown herein. The conduits It extend laterally `fromheader Iii, thence upwardly and-'horn 'T45 zontally to header II. Each of these conduits may be constructed fromv a single length of'tubing and bent into the required'form or they may be provided by two straight lengths of conduit connected by a 'U-shaped end connection-as dcw sired. A plurality of dns I@ of any desired shape or form are secured to and bridge the horizontally extending portions ofconduits i6 to increase the heat absorbing capacity ofthe evaporator. The particular shape and arrangement of the lnns I t t. 5 5- form no part of my invention, The upperheader zontally across the interior thereof andis secured to the inner walls of the cylindrical header l I.

Bailie I1 is providedwith an opening vfor receiving the extension or stand pipe I5 cooperating with the outlet connection I 3. Tiiisbaie I 'I is positioned above the point of 'communication Voi.

conduits Il with header Il and extendsfrom the front wall of header Il to a point-spaced from therear-wall thereof. The space 'between the end oi' baille I'I and the rearjwall o1 header v1i provides a passage I8 for permitting refrigerant to flow from below the baille to the outlet connection I3' of theheader II A( see Fi'g. 1). A tubular lmember I9 is sealed to the front' wall or header II and extends into'the header above the baille I1 and is'clo'sed at its inner end to'form a well for the reception ofa thermostat bulb to -be vhereinafterniore fully referred to.

. Referring toFig. 1, the refrigerating system or evaporator or in the .low pressure portion of the system. Evaporated o r gaseous refrigerant is withdrawn from the evaporator. bythe compressor, through the vaporreturn conduit 32. 'Ihe expansion valve 2'5 of the system shown is preferably of the type disclosed in the patentto Harry B. Hull, No. 1,834,949 of December d, i931. In

such systems. the expansion valve controls the ow of liquid refrigerant into the evaporator in f response to the pressure existing within the evaporator as is fully described in said patent to' In applicantfssystem, like in the Hull patent, there is employed means for modifying the action oi.' the expansion valve to obtain certain results. Therefore, in order to keep liquidrefrigerant distributed throughout theentlre evaporator or te maintain a predetemmee: revel of liquid re-A frigerant in the evaporator I employ a thermostat bulb 35 containing .any suitablel 4eirpansible and 'contractibleii'uid.'4 Bulb 3B is mounted in the well I9 of the evaporator (see Fig. 2i andis connected with theexpansion valve 2'@A by? the-con` duit isee-Flgdland). Theexphnsion valve 2 is 1210111121157 adjusted t0 maintain the lev'el 7 of iiquidrefrigerantxwithintheevaporator at a 'desired' point; preferably imiiiedniteiy` below the 'justed to normally maintain the level of liquid refrigerant within the evaporator immediately below the baille I1. The uid content of thermostat bulb 35 is such that as long as no liquid yrefrigerant is present inthe header II above the baille I1 its influence on valve 21 is negligible and valve 21 operates normally to admit liquid refrigerant to the evaporator as needed in accordance with the rate of evaporation thereof in the evaporator. However, if and when during. certain refrigeration demands upon the evaporator, liquid refrigerant enters the space above the baille I1 in header II, the refrigerant will contact with the wall of the well I9 and consequently' the thermostat bulb since the thermostat bulb is preferably in intimate thermal contact with walls of the well. The temperature of the bulb 35, and consequently itsl fluid content, will be lowered by the increased quantity of liquid refrigerant in the evaporator and' the fluid in bulb 35 and conduit 36 will contract. contraction of the uid in bulb 35 and conduit 36 effects thevoperationof valve 21 in that it closes same to prevent further ingressof liquid. refrigerant to the evaporator. This function of the thermostat to modify the operation of the expansion valve 21 is fully described in the patent to Hullheretofore referred to and for this reason it is believed to be unnecessary to herein describe the operation of valve 21 and the control thereof by thermostat 35 in detail. Obviously, after liquid refrigerant contained in the header II of the evaporator above the baiile4 I1 therein evaporates, the temperature of the thermostat will again rise and permit the expansion valve 21 to operate normally and to open and close in response to pressure within the evaporator. The extension or stand-pipe I5 cooperating with the outlet connection l3 of the evaporator serves -to prevent liquid refrigerant from flowing into the suction line 32 of the system at all times and particularly during presence of liquid refrigerant in header I'I above baille I1.

The arrangementl of baille I1 and its cooperation with the stand-pipe I5 further prevents liquid refrigerant from being splashedv `into the suction line 32 of the system during violent boiling of the refrigerant in the evaporator and thus enables the apparatus to operate efliciently to produce refrigeration only within the evaporator portion of thesyster'n. AThese features have been extremely difficult tofobtain in evaporators for such systems wherein the refrigerant conveying or distributing conduits have been connected in parallel because of the fact that violentv or abnormal evaporation of refrigerant may occur in certain ofthe conduits while normal evaporation enligne' evaporator .structuregellminates alll problems heretofore encountered in the constructionrof evaporators* including conduits connected in parallel circuit relation vand permits substantially the entire cooling conduit area of the evaporator to be flooded with liquid refrigerant.

From the foregoing, it can be determinedl that I have provided an improved evaporator for re-v lthe type disclosed as an-evaporator wherein liqoccurs in other co ts. However, my improved uid refrigerant is admitted thereto by-a Avalve I actuated by a float responsive to a predetermined level of liquid refrigerant in the evaporator.

That is, substantially the entire cooling surface of the evaporator is in intimate thermal contact 'with liquid refrigerant, and;` at the same time,

liquid refrigerant is prevented under all conditions of loperation from entering the low presform, it is to be understood that4 other formsv v might be adopted, all coming within the scope of the claim which follows.

What is claimed is as follows:

A refrigerati'ng system comprising in 'combination, an evaporator, said evaporator including a header having a liquid refrigerant inlet, said vevaporator also including another header dising a gaseous refrigerant outlet, said another header being larger than said first named header and lying parallel thereto, aplurality voi refrigerant distributing conduitsA connected in parvposed* above saidrlrst named header andhavallel to said headers and extending outwardly therefrom, a plurality of fins secured to and disf posed at right angles to said refrigerant distributing conduits for increasing the heat transference surface of the evaporator, means for circ'ulatingy liquid refrigerant to said evaporator and for withdrawing gaseous refrigerant therefrom, a valve for controlling the flow of liquid refrigerant into said evaporator through the inlet provided in said rst named header, a. thermostatv positioned within'said another header and responsive to the temperature of refrigerant flowing from said conduits to said another header'.

HERMAN J DICK. 

